[seqfan] Re: Jacobsthal function

[Charles Greathouse]

On the face of it that gives information only on the computation of A048670.

Charles Greathouse
Analyst/Programmer
Case Western Reserve University

On Sat, Sep 8, 2012 at 9:06 PM,  <allouche at math.jussieu.fr> wrote:
> Hi
> Does the following help?
> http://www.ams.org/journals/mcom/2009-78-266/S0025-5718-08-02166-2/S0025-5718-08-02166-2.pdf
>
> best
> jp
>
>
> Charles Greathouse <charles.greathouse at case.edu> a écrit :
>
>> The Jacobsthal function, A048669, is an important sequence which
>> appears in many contexts (e.g., bounding the size of prime gaps;
>> finding the least prime in an arithmetic progression; bounding the
>> state complexity of regular languages). It is defined as the maximal
>> distance between numbers relatively prime to n.
>>
>> How is it computed? The sequence is marked easy, and yet the only
>> program listed is very slow, doing calculations on all numbers up to
>> n.
>>
>> A search reveals a body of literature on computing A048670 =
>> a(prime(n)#) efficiently, but nothing on the sequence itself. Perhaps
>> it is obvious but I can't immediately see it.
>>
>> Charles Greathouse
>> Analyst/Programmer
>> Case Western Reserve University
>>
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